Ore-concentrating table.



No. 7l6,205.

' Patented Dec. l6, |902.. v w. a. noun.

DRE CONCENTRATING TABLE.

rA lieinion filed July 25, 1902.) (N o M 0d a I.)

2 Sheets-Sheef I.

s- Sheet 2.

BSheet Patented Dec. l6, I902.

W G. D O D D ORE CDNGE NTBATING TABLE.

(Apphcatlon filed July 25, 1 902 m: NORRIS PETERS 6o, Puma-Lind wnsmmsrc w u of (No Model.)

WILLIS c. DODD, or SAN FRANCISCO, CALIFORNIA.

ORE-CONCENTRATING TABLE.

SPECIFICATION forming part of Letters Patent No. 716,205, dated December 16, 1902.

Application filed July 25, 1902. Serial No. 116,944. (No model.)

To aZZ whom, it may concern.-

Be it known that I, WILLIS G. Donn, a citizen of the United States, residing in the city and county of San Francisco,:State of California, have invented certain new and useful Improvements in Ore-Concentrating Tables; and I do hereby declare the followingto be a full, clear, and exact description of the same.

The present invention relates to concentrating-tables, and more particularly to that class of concentrating tables known as transversely-inclined reciprocating concentrating-tables, theworkingsurfaces of which are provided with a series oflongitudinal deflecting slats or. riftles which discharge the mineral they collect upon a smooth or unriffled portion of the table for final washing and separation by subjecting the material fed thereon to the action of a flow'of clearwater, the invention pertaining more particularly to the manner of arranging and applying the deflecting slats or riftles to the working surfaces of such tables,-together with other details hereinafter explained.

The object of my improvement is, first,-to increase the capacity of such concentratingtables without enlarging the working surface thereof, and, secondly, to increase their efficiency by producing less of the mixedprodnct,termed middlings,, which requires subsequent treatment. I attain these objects by the manner of rifding thetables illustrated in the accompanying drawings, wherein.

Figure 1 is a top plan-view of the concen trator. Fig. 2 is an enlarged top plan view of the table detached fromits frame; and

Fig. 3 is a cross-sectional end view in elevation,taken on line mm, Fig. 1, of the drawings-.-

Various United States Letters-Patent have been granted for concentrating-tables having riffles arranged on the working face thereof for the separation of the valuable particles as the pulp is treated thereon. Perhaps the prior art may be said to be substantially de-. fined by United States Letters Patent No. 247,629,.granted Garvin, September 27, 1881; United States Letters Patent No. 258,879, granted Blatchly et al., June 6, 1882; United States Letters Patent 190,533,362, granted Lampert, January 29, 1895, and United States Letters Patent No. 590,675, granted Wilfley,

line.

advantageous features of the prior tables and eliminates supposed defects. It utilizes the arrangement of riftles of the Lampert patent, No. 533,362-that is, arranges the rifl'iles to extend from the head of the table, feeding the pulp thereto at substantially right angles to the riffles, and imparts to the table a jolting movement in the direction of the line of riffles. To the riffles is given the advancing terminal feature of the Garvin patent, No. 247,629, and the plain or unriffled portion of the table set forth in the Blatchly et al. patent, No. 258,879, and disclosed to a limited extent at the terminal of the rifdes of the said Lampert patent. In the said Lampert and the said Wilfiey patents the longitudinal riffies extend from the head of the table, are arranged diagonally across the working face thereof, terminate at a plain or unrifiied portion, and the jolting movement of the table is in the line of rifles. The riffles of the Wilfley table extend onto the plain or unriffled portion with advancing terminals, while the Lampert riffles terminate in the same This. extension or advancing terminals of theWilfiey riffles give riffles of increasing length, each extending from the head of the table a distance beyond its preceding riffle onto the plain or unriflied portion of. the table. This arrangement of the rifflesallows of the material assuming a natural diagonal line ofmovement over the smooth surface of the. table and subjects it to repeated washings in its passage from riffie to riffle. With this form of table the material caught by the uppermost and shortest riffle, consisting of mineral and gangue, is discharged upon the the upper edge of the table,

smooth or unriffled portion of the table. The action of the flowing water, which is fed upon separates and carries the gangue, which is lighter than the mineral, downward to the advanced terminal of the next riffle, while the mineral remains on the smooth or unriffled portion of the table and, due to the motion given the table, is carried forward over the smooth surface toward the tail of the table, where it is finally discharged into a receptacle provided for the purpose. In actual practice a slight portion of the mineral caught by the uppermost and shortest riffle will be carried downward with the gangue to the advanced terminal of the riffle below, mixing with the material caught by this riffle, which is discharged upon the smooth surface and is again subjected to the separating action of the water, as before, washing the gangue downward to the advanced terminal of the riffle below, While the mineral continues on its travel over the smooth surface to the tail of the table and is discharged, this operation successively repeating itself down to the lower riifles on the table, leaving an unseparated quantity of material termed middlings. It is obvious that the operation described could not be successfully performed should the table be given a steep transverse inclination or should the flow of water fed upon the upper edge of the table be heavier than that sufficient to Wash the gangue transversely downward without disturbing the mineral clinging to the smooth surface; otherwise the mineral and gangue would both be carried transversely downward and entangled among the advancing terminals of the rifiles, producing middlin-gs only. Thus it will be seen that the capacity of the table is governed by the delicate conditions namedt. 8., a slight transverse inclination and a light flow of water transversely across the smooth surface of the table.

My improvement consists in placing the riffles upon the working face of a transverselyinclined concentrating-table in such a manner that all the mineral collected by the riffles will be discharged upon and guided by the terminals of the riffles along the line of its natural path of travel over the table, due to the forces acting upon it, caused by giving the table a greater transverse inclination than can be employed in concentrating-tables of this class as usually constructed when a transverse flow of water is used sufficient to move the mineral down ward across the smooth or unruffled portion of the working face of the table. The forces acting upon and governing the mineral in its travel over the table under the conditions named are inversely the same as those acting upon a projectile discharged from a gun, the constant flow of Water acting as gravity and the impulse given the table acting as the projecting force. These forces being known, the same formula may be applied to determine the trajectory or path of the mineral over the table as is employed to determine the trajectory of a projectile, and when this is done the natural trajectory or path of the mineral over the table will be found to follow a curve approximating an inverted parabola.

By refering to Fig. 1, which is a plan view of a transversely-inclined reciprocating concentrating-table provided with means for adjusting the transverse inclination as required and fitted with my improved form of riffiing, the area inclosed by the letter Ais the working face of the table, usually covered with linoleum. The area inclosed by the letter B is that portion of the table covered or fitted with my improvement, consisting of a series of mineral-collecting rifiles. ally tapering strips of wood, and they extend longitudinally from the overflow-riffle O toward the foot A of the table, the terminals of these riflles advancing to the curved line or path D approximating an inverted parabola. The area represented by letter B is that portion of the table which forms a smooth runway or trough, which is utilized for the cleaning and conveying of the mineral to its discharge-point at the foot of the table. The stationary water pipe or distribut-er O is suitably supported above the table. From this pipe clear water through suitably-controlled openings or jets is delivered to the table a short distance from the terminals or dis charge ends of the riffles. is located near the head of the table, at its upper edge, which delivers the pulp or material to be concentrated upon the table above the riffles. A sluice or launder E connects the feed-box with any suitable device for crushing the material. Any suitable mechanism for imparting a variable longitudinal reciprocating motion to the table may be employed, that illustrated in the drawings being a simple and well-known form.

The operation is as follows: The table is placed upon its frame or baseE with sufficient elevation to give a longitudinal inclination toward the head F. The table is then given a transverse inclination sufficient to cause the pulp to flow rapidly and smoothly downward over the riffle. Power being applied to the driving mechanism a longitudi nal reciprocating motion is then imparted to the table, which motion has a tendency to carry the material fed upon the table forward toward the foot A. Pulp, consisting of a mixture of water, gangue, and mineral, is now introduced by means of a sluice into the feedbox D, from which it is delivered onto the table above the riffles and flows transversely downward over the same. The mineral contained in the pulp being heavier than the gangue settles between the riflies and is caught by them. A large portion of the slimy water introduced with the pulp in passing transversely downward over the table The feed-box D These are usuthis water carry in suspension any of the fine particles of mineral, the same will be conducted into a sluice provided for the purpose of conveying it to a settling-tank, thus recovering the fine particles of suspended mineral that would otherwise be lost. The gangue or worthless portion of the .pulp continues on its course, flows over the lower side of the table, and is permitted to escape. The mineral which has been caught by the riffles is carried, due to the motion imparted to the table, longitudinally forward along the rifiles and is discharged with more or less gangue into the smooth runway or trough, Where it is subjected totheaction of a flow of clear water delivered upon the table from the water pipe or distributor O. The action of the Water upon the material discharged by the riffles and the cleaning and separation of the mineral in its travel through the runway or trough toits point of discharge will be more fully understood by referring to Fig. 2 of the drawings, which is an enlarged plan View of the tableand that portion upon which the operation is performed. As soon as the material-a mixture of mineral and ganguewhichhas been collected by the first rifile is discharged upon thesmooth portion of the table it comes in contact with the flow of water delivered from the pipe 0 and is carried down and mixed with the discharge of the riffle below. This mixture in turn is carried down and mixed with the discharge of the next riiiie below, this operation successively repeating itself until a pointsay 'yin the path of the mineral has been reached where the trajectory begins to flatten. At

i this point the downward speed of travel is diminishedand the mass of collected materialbegins to come under greater control of the motion imparted to the table, which agitates the material, consisting of mineral and gangue, causing the mineral to settle and the gangue to rise to champ and be carried off by the overflow of the clear water. The mass of clean mineral is gradually carried down of gangue.

. collected and discharged on its path. When theband of mineral has reached the terminal of the last riffie, the fringe of gangue G at the lower edge ofthe table, mixed with small particles of mineral, is sliced off by using the hinged pointer G, and the middlings thus obtained are discharged into the hopper .H, from whence they are taken and returned to the table by means of any suitable device to be again treated. The mineral continues 011 and is discharged from the table over the apron'I-I" into any suitable receptacle pro-' vided for the purpose.

The longitudinal inclination given the table is an important factor, as it gives a slight diagonal direction to the flow of water-at the head of the table, which tends to retard the lighter gangue from being discharged by the riftles, but does not interfere with the discharge of the mineral which the riffies may collect.

This method of riffiing enables the upper riftles to be used for the purpose of roughly collecting the mineral in mass and the lower riffies for guiding, cleaning, and separating it from the gangue, performing these two operations while the mineral is traveling over the table on a natural trajectory, due to the forces acting upon it, forming a curved line approximating an inverted parabola.

It is obvious that the described treatment of mineral in mass on a table of this type is much more rapid than with the ordinary method employed, and the middlin gs produced are reduced to a minimum. The means herein described of treating mineral on a table of this class by the use of a series of longitudinal riffies having advancing terminals terminating in a curved line approximating an inverted parabola is believed to be new. The

inclination of the table is controlled by means of the adjusting devices H which work against frame E. The flow of the pulp is indicated by arrow 3 and that of the separated material by arrows 4, the middling being designated by arrows 5.

Having thus described the invention, what is claimed as new, and desired to be protected by Letters Patent, is-

l. A transversely-inclined concentratingtable having a movement whose tendency is to carry the material fed thereon longitudinally forward toward the tail or foot of the table, said table being provided with a number of longitudinal riffies, the terminals of said riftles successively advancing and terminating upon the surface of the table in a curve-line approximating an inverted parab- 01a so as to permit of a band of discharge,

leaving a smooth surface onto which the material collected by the riffles is discharged, washed and cleaned by being subjected to the action of clear water, and means whereby water is admitted onto the table for washing the material delivered onto the unriffied portion thereof.

2. A concentrating-table provided with means for imparting thereto a longitudinal and a transverse inclination, the working surface of said table being provided with a number of riffles extending longitudinally from an overflow-riflle toward its foot, the terminals of said riffies successively advancing and terminating upon the surface of the table in acurve-line, approximating an inverted parabola, a smooth or unritfled surface to the table onto which the material collected by the riflie is cleaned and separated by being subjected to the action of clear Water, means for imparting a reciprocating motion to the table, devices for giving thereto a longitudinal and a1atera1inc1ination,and means where by Water is admitted onto the table for washing the material delivered onto the unrifiied portion thereof.

In witnesswhereof I have hereunto set my hand.

WILLIS G; DODD. Witnesses:

HARRY J. LASK, WALTER F. VANE. 

